A diffractive optical element, such as a holographic plasma lens, can be made by direction two laser beams so that they overlap in a nonlinear material, to form an interference pattern in the nonlinear material. The interference pattern can modify the index of refraction in the nonlinear material to produce the diffractive optical element. The interference pattern can modify the distribution of plasma for the nonlinear material, which can adjust the index of refraction. A third laser beam can be directed through the diffractive optical element to modify the third laser beam, such as to focus, defocus, or collimate the third laser beam.

Methods of recording volume Bragg gratings are provided. A recording medium includes matrix polymer precursor, inimer comprising a polymerizable functional group and a controlled radical reactive group, photoinitiator more reactive with the polymerizable functional group than the controlled radical reactive group in the presence of an excitation source, and a photoredux catalyst. The medium is cured to form a support matrix. The medium is exposed to the excitation source, forming a latent grating having bright fringes and dark fringes. Polymerized inimer is more concentrated in the bright fringes than in the dark fringes. A high refractive index monomer reactive with the controlled radical reactive group is diffused into the medium and exposed to light to cause controlled radical polymerization between the high refractive index monomer and the controlled radical reactive group of the polymerized inimer, driving up a refractive index of the bright fringes relative to the dark fringes.

The present disclosure relates to improved holographic reconstruction device and a method. In one aspect, the present disclosure relates to improved holographic reconstruction device and method that can measure a digital hologram regardless of optical characteristics of an object to be measured, by an all-in-one type system integrating a transmissive system that measures an object transmitting light and a reflective system that measures an object reflecting light.

This application relates to a see-through head-mounted display using recorded substrate-guided holographic continuous lens (SGHCL) and a microdisplay with narrow spectral band source or laser illumination. The high diffraction efficiency of the volume SGHCL creates very high luminance of the virtual image.

A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and −1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.

An optical reflective device referred to as a skew mirror, having a reflective axis that need not be constrained to surface normal, is described. Examples of skew mirrors are configured to reflect light about a constant reflective axis across a relatively wide range of wavelengths. In some examples, a skew mirror has a constant reflective axis across a relatively wide range of angles of incidence. Exemplary methods for making and using skew minors are also disclosed. Skew mirrors include a grating structure, which in some examples comprises a hologram.

An optical device and an eye-tracking system to suppress a rainbow effect are provided. The optical device includes a grating. The grating includes at least one substrate and a grating structure coupled to the at least one substrate. The grating structure is configured to diffract an infrared light beam and transmit a visible light beam with a diffraction efficiency less than a predetermined threshold.

A method for observing a sample by lensless imaging, in which a sample is positioned between a laser diode and an image sensor, the laser diode being supplied with a supply current whose intensity is less than or equal to a critical value. This critical intensity is determined during preliminary operations, during which the intensity is initially greater than a laser threshold of the diode. By observing the image formed at the image sensor, the intensity is decreased until an attenuation of the interference images on the formed image is observed, the critical intensity corresponding to the intensity at which this attenuation is optimum.

A method of producing information from at least one camera image of an object, including: A) recording raw image data of the at least one camera image, B) evaluating the raw image data by a mathematical linkage to produce combination image data, C) deriving the information from the combination image data, D) outputting the information, E) determining an actual measure for a data quality of the raw image data prior to or after evaluation steps in step B), F) determining a deviation between the actual measure for the data quality and a target measure for the data quality of the raw image data of at least one camera image, and G) again recording all raw image data of those camera images, for which the deviation determined in step F) is greater than a predetermined threshold value and repeating at least one evaluation step from step B) and steps C) to F) either until the deviation determined in step F) for the raw image data of all camera images from the plurality of camera images is less than the threshold value or until a predetermined termination condition is fulfilled.

A lensless holographic imaging system having a holographic optical element includes: a coherent light source for outputting a first light beam and a second light beam, wherein the first light beam irradiates a first inspection plane to form first object-diffracted light; a light modulator for modulating the second light beam into reading light having a specific wavefront; a multiplexed holographic optical element, wherein the first object-diffracted light passes through the multiplexed holographic optical element, and the reading light is input into the multiplexed holographic optical element to generate a diffracted light beam as system reference light; and an image capture device for reading at least one interference signal generated by interference between the first object-diffracted light and the system reference light. The lensless holographic imaging system has a relatively small volume and relatively high diffraction efficiency.